Merck & Co.
US pharmaceutical company, known as MSD outside the US and Canada.
Merck's Ervebo, licensed only against Zaire Ebola, is now being tested against Bundibugyo: MSF began vaccinating about 20,000 frontline workers in DR Congo on 19 September 2026, while a separate ring-vaccination trial is still planned.
Last refreshed: 4 October 2026 · Appears in 1 active topic
Why can't Merck's licensed Ebola vaccine cover the Bundibugyo species?
Timeline for Merck & Co.
Developed Ervebo against the Zaire species
Pandemics and Biosecurity: WHO: 2,000 Congolese workers get ErveboHit by NotPetya in June 2017
Cybersecurity: Threats and Defences: Mentioned in: Boston Scientific likely to miss guidanceProvided manufacturing expertise via Hilleman Laboratories
Pandemics and Biosecurity: CEPI puts a Bundibugyo vaccine in trialsBackground
Merck & Co., known as MSD outside the United States and Canada, is one of the world's largest pharmaceutical companies. Its portfolio spans cancer drugs, vaccines, animal health and hospital medicines.
Its vaccines include Ervebo, the rVSV-ZEBOV shot licensed against the Zaire species of Ebola that caused the 2014-2016 West African epidemic. A separate $30m programme is improving MSD's manufacture of that vaccine. Ervebo has no licence against other Ebola species, which is why the 2026 Bundibugyo outbreak turned it into a trial product.
Merck also reaches diseases too commercially marginal to develop alone through partnerships. It co-owns Hilleman Laboratories, a Singapore-based joint venture with the Wellcome Trust. On 31 July 2026 Hilleman put the first vaccine built specifically for Bundibugyo ebolavirus into clinical-trial production, drawing on Merck's manufacturing know-how rather than its core research budget.
Ervebo faces an untested Ebola species
Merck's Ervebo is licensed against Zaire ebolavirus, not the Bundibugyo species behind DR Congo's 2026 outbreak. Even so, the International Coordinating Group released 70,000 doses to DR Congo on 20 August, and about 2,000 health and frontline workers had received it by 10 September. MSF's BRAVO study, which opened in Bunia on 19 September, is giving Ervebo to about 20,000 frontline staff across Ituri and North Kivu.
WHO still plans its own randomised ring-vaccination trial of 20,000 doses, the test that could show whether Ervebo protects against Bundibugyo, and expected it to start in October or November in Ituri, where cases have fallen since mid-August. Merck's other link to the outbreak runs through Hilleman Laboratories, whose Bundibugyo-specific candidate entered trial production on 31 July.
What is Merck & Co.?
Does Merck make an Ebola vaccine?
How much is CEPI funding Merck's Bundibugyo vaccine candidate?
Written with AI from Lowdown's published reporting. Not individually reviewed by an editor. Updated 4 October 2026. Editorial standards.